1. Field of the Invention
The subject invention generally pertains to motion sensing digital cameras for monitoring and photographing wildlife and more specifically pertains to such a camera that includes a sleep mode for conserving the camera's battery life between shots.
2. Description of Related Art
There are a wide variety of cameras for various uses. Wildlife observation cameras, however, are particularly unique for all their special needs. Typical wildlife cameras are usually left unattended in an area where wildlife is expected, and a motion detector is often used for triggering the camera when an animal appears. Some of the unique needs of wildlife cameras include a motion detector or some other camera-triggering device; weather protection; an illuminating flash for taking pictures at night; rapid response for taking pictures of fast animals; and logic for adjusting the camera's function under changing conditions such as amount of daylight, outdoor temperature, size of animal, and speed of animal.
A particularly important feature of a wildlife camera is its battery life. Such cameras are usually set up in the woods or other remote areas where outside electrical power is unavailable. Since such cameras may be expected to run continuously on their own for hours, overnight, or even several days, the camera's battery may need to be quite large and bulky. Conceivably, a camera could be put in a sleep mode to conserve energy between shots; however, the process of “waking” a digital camera typically involves setting its gain (AGC or automatic gain control), which can take a moment before a picture can be taken. Even a few milliseconds, unfortunately, can mean the difference between capturing and missing a shot of a fast moving animal, such as a bird in flight.
Some cameras, as disclosed in U.S. Pat. No. 6,621,519, the current white balance is adjusted on the basis of previously stored data. Unlike the automatic gain control of a black and white camera, however, white balance pertains to color adjustment. A picture, for example, taken of a room with yellow walls and nothing white in the room to serve as a white reference may result in picture with a maladjusted white balance, whereby a photograph of the walls may appear white rather than yellow.
Other cameras of interest are disclosed in U.S. Pat. Nos. 5,742,340 and 5,610,654. The '340 patent discloses a camera with an ambient light sensor, whereby the camera does not require high speed automatic gain control responses when objects move rapidly across the camera's field-of-view. The '654 patent discloses a camera that uses a Flash EPROM memory card, whereby images on the card can be downloaded to a computer or a printing device.